SqlDataReader.GetOrdinal(String) Method

Definition

Namespace:

Microsoft.Data.SqlClient

Assembly:

Microsoft.Data.SqlClient.dll

Package:

Microsoft.Data.SqlClient v5.2.0

Gets the column ordinal, given the name of the column.

public:
 override int GetOrdinal(System::String ^ name);

public override int GetOrdinal (string name);

override this.GetOrdinal : string -> int

Public Overrides Function GetOrdinal (name As String) As Integer

Parameters

name

String

The name of the column.

Returns

Int32

The zero-based column ordinal.

Implements

GetOrdinal(String)

Exceptions

IndexOutOfRangeException

The name specified is not a valid column name.

Examples

The following example demonstrates how to use the GetOrdinal method.

using Microsoft.Data.SqlClient;

class Program
{
    static void Main()
    {
        string str = "Data Source=(local);Initial Catalog=Northwind;"
            + "Integrated Security=SSPI";
        ReadGetOrdinal(str);
    }

    private static void ReadGetOrdinal(string connectionString)
    {
        string queryString = "SELECT DISTINCT CustomerID FROM dbo.Orders;";
        using (SqlConnection connection =
                   new SqlConnection(connectionString))
        {
            SqlCommand command =
                new SqlCommand(queryString, connection);
            connection.Open();

            SqlDataReader reader = command.ExecuteReader();

            // Call GetOrdinal and assign value to variable.
            int customerID = reader.GetOrdinal("CustomerID");

            // Use variable with GetString inside of loop.
            while (reader.Read())
            {
                Console.WriteLine("CustomerID={0}", reader.GetString(customerID));
            }

            // Call Close when done reading.
            reader.Close();
        }
    }
}

Remarks

GetOrdinal performs a case-sensitive lookup first. If it fails, a second, case-insensitive search occurs (a case-insensitive comparison is done using the database collation). Unexpected results can occur when comparisons are affected by culture-specific casing rules. For example, in Turkish, the following example yields the wrong results because the file system in Turkish does not use linguistic casing rules for the letter 'i' in "file". The method throws an IndexOutOfRange exception if the zero-based column ordinal is not found.

GetOrdinal is kana-width insensitive.

Because ordinal-based lookups are more efficient than named lookups, it is inefficient to call GetOrdinal within a loop. Save time by calling GetOrdinal once and assigning the results to an integer variable for use within the loop.